Tokyo police and immigration officials took more than 20 Chinese, Iranian and other foreigners in the Shinjuku area into custody Monday night on suspicion they have been overstaying their visas.
At around 8 p.m. more than 100 police and immigration officers blocked off four alleys in Shinjuku Ward's Okubo area, a thriving cluster of ethnic restaurants, Asian goods shops and small hotels where many foreign workers reportedly live.
The officials then ordered those on the street and inside the buildings to present identification and apprehended those who were overstaying their visas. Witnesses said many foreigners tried to flee.
The area, just north of the Kabukicho entertainment district, is known to be rife with prostitutes and drug dealers, police said.